Psalm 110:4
The LORD has sworn
and will not change his mind,
"You are a priest for ever
after the order of Melchizedek."
Jesus established a New Priesthood. It was a priesthood that offered, not the blood of goats and bulls, but his own blood, in perfect sacrifice to God the Father. That sacrifice was offered once for all on Calvary. But our need to have access to that sacrifice is ongoing. So Jesus took gifts of bread and wine (like Melchizedek did long ago), transformed them into his Body and Blood, and commanded his apostles to do likewise "in memory of me." In short, he founded a new priesthood for his "new covenant in my blood." That priesthood remains with us to this day, faithfully performing the sacrifice of the Mass, whereby God makes present in the here and now the one sacrifice offered so long ago on Calvary. Today, don't forget to thank your priest for his faithfulness.